1. Field of the Invention
This invention relates generally to the process of the removal of fat from meat and more particularly, a continuous process for the removal of fat from ground meat at a low temperature using a centrifuge without changing the characteristics of the meat protein.
2. Description of Prior Art
The production of low fat foods has become increasingly important in recent years as the negative health effects of excess fat consumption have become widely known. In order for a low fat food to become commercially successful, it must satisfy the flavor, appearance, and texture expectations of the consumer at a price that is not out of line with the cost of analogous full fat foods. Processed meats and foods containing significant amounts of meat are among the most difficult types of foods to make with low fat levels that meet consumer expectations at a reasonable cost.
Most recently the United States Food and Drug Administration and Department of Agriculture have tightened the requirements for reduced fat foods. These changes have resulted in requiring lean meat to have less than 10% fat and extra lean meats to have less than 5% fat. Low fat foods are defined as containing less than 3 grams of fat per serving or less than 3 grams of fat per 100 grams of food if the serving size is less than 100 grams. These new requirements have made it even more difficult to produce "lean", "extra lean", or "low fat" meat products which meet consumer expectations in an economical manner.
The most common meats used to make low fat products are trimmed whole muscle cuts such as ham meat, skinless chicken breast meat, skinless turkey breast meat, etc. While these lean meats have good acceptance in the marketplace, they are very expensive. The use of trimmed whole muscle meats in processed meat products such as sausage or meat containing foods such as chili or stew make the low fat products much more expensive than the traditional full fat products which use meat or poultry trimmings as ingredients.
Many processes have been proposed to remove fat from meat trimmings. These processes have been unsuccessful in producing low fat meats either because the meats were inherently poor in protein quality or because the processes altered the original functionality of the meat. In either case the resulting reduced fat meats were inferior ingredients in processed meats or food products. These processes have generally taken the following approaches to removing fat from meat or poultry trimmings.
One approach has been to wash the finely divided meat with a solution of water and/or additives such as acids to remove fat and soluble proteins from coagulated proteins. The coagulated meat proteins are then used as ingredients in food products. These processes not only remove fat, but also proteins that give meat its characteristic color and flavor. These changes in composition produce a reduced fat "meat" that is significantly different than the initial lean meat fraction and suffer losses in yield that increase the cost of the finished product. Examples of this type of process are U.S. Pat. Nos. 5,167,977 and 5,221,554 as well as a report in the Journal of Food Science volume 53, no. 6, pp. 1615-1617 (1988).
Another approach has been to recover fat using low temperature rendering processes. These processes involve recovering fat from animal fatty tissues at temperatures of 90.degree.-120.degree. F. The resulting reduced fat protein fraction is claimed to be used as a minor component in making processed meat products. This reduced fat protein fraction typically contains a high level of collagen which gives it poor binding properties for processed meats such as sausages. Examples of this approach are given in U.S. Pat. Nos. 3,270,041 and 3,449,315.
Another approach to reducing fat in meat is to centrifuge the mechanically deboned chicken at high speed to produce a fat fraction, an aqueous protein solution and a protein precipitate, each fraction comprising about one third of the original starting weight. This process results in a significant loss of product as the yield is only about 33% of the starting weight when the original material contained about 15-20% fat. This approach is described in the Journal of Food Science volume 38 pp. 279-281 (1973).
The process of this invention addresses the problems associated with the prior art and produces low fat meats which maintain the color, flavor, and functionality of the original meat. The low fat meats produced with this invention can be used to make a variety of processed meat products and can be used as the sole meat ingredient in other low fat foods.